5 sentences that need help correcting

Could you please help me correct these?

1 Prices only dropped 20 dollars/by 20 dollars/(by) 20 percent

2 She is bound to have made a mistake

3 Lets see which/what jeans she wears tomorrow.

4 Is it possible that someone could control what I do./Might it be possible for someone to control what I do.

5 I took me till to do my work but I always manage to get home at the right moment/time when my parents were sleeping.

Thank you